Drive finger for a clipper blade

ABSTRACT

A DRIVE CONNECTION BETWEEN A VIBRATORY ARMATURE AND A RECIPRICABLE CLIPPER BLADE WHICH IS FORMED TO PROVIDE A RECESS IN ITS SURFACE REMOTE FROM A MATING STATIONARY BLADE, SAID CONNECTION COMPRISING A SPRING CONNECTED TO THE ARMATURE AND PROVIDED AT ITS DISTAL END WITH A BLOCK RECEIVED IN SUCH RECESS, THE BLOCK BEING FORMED TO MAINTAIN MOVABLE POINT- OR LINE-CONTACT WITH OPPOSING BOUNDARY   WALLS OF THE RECESS TO PRESS THE RECIPROCABLE BLADE INTO COOPERATIVE CONTACT WITH THE STATIONARY BLADE AND TO TRANSMIT THE VIBRATORY MOTION OF THE ARMATURE TO SAID RECIPROCABLE BLADE.

March 16, l97l I v. H. WILLIAMS DRIVE-UFZINGERFOR A CLIPPER BLADE Filed Dec. 11, 1968 2 Sheets-Sheet 1 Fig. 2

INVENTOR VERNON H. WILLIAMS BY YWM T ORNEYS Fig.5

March 16, 1971 v, w s I 3,570,122

DRIVE FINGER FOR A CLIPPER BLADE V Filed Dec. 11, 1968 2 Sheets-Sheet 2 Fig. 11 DIBI i 83' 1 1 I 29' 78 75 pl! I :z ve II 82 I|77 80 LL 84 INVENTOR n i Fl8-l3 VERNON H. WILLIAMS 1 13.12 v z/OOZQWWW ATTORNEYS United States Patent Olhce 3,570,122 DRIVE FINGER FOR A CLIPPER BLADE Vernon H. Williams, Columbus, Ind., assignor to Vernco Corporation, Columbus, Ind. Filed Dec. 11, 1968, Ser. No. 782,829 Int. Cl. B26b 19/02 US. Cl. 30210 2 Claims ABSTRACT OF THE DISCLOSURE A drive connection between a vibratory armature and a reciprocable clipper blade which is formed to provide a recess in its surface remote from a mating stationary blade, said connection comprising a spring connected to the armature and provided at its distal end with a block received in such recess, the block being formed to maintain movable pointor line-contact with opposing boundary walls of the recess to press the reciprocable blade into cooperative contact with the stationary blade and to transmit the vibratory motion of the armature to said reciprocable blade.

The present invention relates to a vibratory drive connection primarily designed for use in a hair clipper comprising a pair of mating toothed blades, one of which is reversely driven by the armature of a vibratory electric motor. One known type of such a drive connection is disclosed in the patent to L. J. Wahl, No. 2,640,261, issued June 2, 1953. It has been found that the drive connections in such known vibratory clipper devices are relatively noisy and subject to wear, but the reasons for such disadvantages have not heretofore been clearly understood.

In such previously-known drive connections, it has been customary to use a particular form of commercial, reciprocatory blade which is formed to provide a lower, flat surface, slidably received upon the upper, flat surface of a stationary blade, and formed in its upper surface with a recess which is elongated in the direction of travel of the blade and which is defined, at each of its lateral ends, by flat surfaces which converge laterally and which additionally are inclined downwardly and toward each other. Heretofore, a spring, fixed to the vibratory armature and extending toward the movable blade, has carried a finger, enterable in the blade recess and shaped to provide a plurality of fiat surfaces which conform to the above-described flat surfaces, with the spring flexed to press the movable blade yieldably into engagement with the stationary blade. The finger, when at rest, thus has plural surface contacts of significant area with the recess walls. Since the armature extension must travel in an are lying in a single plane and since that plane is angularly related to the plane of travel of the movable clipper blade, there must be a rocking action somewhere in the drive train between the armature extension and the blade. If the element engaged in the recess is to maintain its plural-surface contact in the recess, then that rocking action must occur in the spring member, by torsion thereof; but the spring member inherently resists such torsion, and the fact is that, in practice, the element engaged in the recess does rock relative to the recess.

Further, the vibratory velocity of the armature is quite rapid and the inertia of the movable blade is considerably higher than that of the element engaged in the blade re 3,570,122 Patented Mar. 16, 1971 cess. Therefore, on each reversal of motion of the armature, the blade tends to overrun the element which is engaged in its recess.

As a result of these two conditions, at least a portion of at least one flat surface on the element engaged in the blade recess will, on each reversal in direction of movement of the armature, leave a corresponding portion of the mating flat surface of the recess boundary; and, as the direction of movement of the blade is subsequently reversed, the separated flat surface portions will be returned smartly to mating contact to produce a slapping sound.

Additionally, as the above-described rocking motion occurs, there will inevitably be some sliding movement between the flat surfaces of the element which is engaged in the recess and the corresponding fiat surfaces of the recess boundaries, with resultant wear.

According to the present invention, the element which engages in the blade recess is formed, at its lateral ends, for non-forming, continuous contact with the inclined and laterally-converging boundary surfaces at the lateral ends of the recess in such a commercial form of movable blade. The expression non-conforming contact, as used in this specification and in the claims appended hereto, means substantially line contact or point contact, as distinguished from extended-surface contact. To achieve that result, the lateral end regions of the element engaged in the recess are part-cylindrical or part-spherical about an axis arranged substantially in the line of movement of the element so engaged. Thus, as the armature vibrates to drive the blade reversely, there is maintained a rolling line contact or point contact between the ends of the engaged member and the lateral boundary walls of the blade recess. Although, as the arc of movement of the armature retreats from the plane of movement of the blade toward each end of the armature stroke and approaches that plane toward the median point of that stroke, and as the blade overtravels the engaged member at each end of the path of movement of the blade, the point or line of engagement bet-ween the recess Walls and the ends of the engaged element will move,

,it will be apparent that point or line contacts (depending upon the shape of the ends of the engaged member) will be maintained by a rolling action, thus eliminating the noisy slapping eifect above described.

The primary obejct of the present invention, then, is to provide an improved drive train between a vibratory element, such as the armature of an electric vibratory motor, and the reversely-movable element of a pair of elements such as the toothed blades of a hair clipper, whereby the drive train is rendered quieter, less expensive and less subject to deteriorating wear.

Further objects of the invention will appear as the description proceeds.

To the accomplishment of the above and related objects, my invention may be embodied in the forms illustrated in the accompanying drawings, attention being called to the fact, however, that the drawings are illustrative only, and

FIG. 2 is a plan view of the clipper of FIG. 1, with parts of the casing broken away to illustrate the drive train more clearly;

FIG. 3 is a plan view of the movable blade, drawn to an enlarged scale;

FIG. 4 is a plan view of a spring member equipped with one form of block for engagement in a blade recess, drawn substantially to the scale of FIG. 3;

FIGS. 5, 6 and 7 are views similar to FIG. 4 but showing modified forms of block means carried by a spring member;

FIG. 8 is a fragmentary perspective view showing a different form of block means carried by a spring member;

FIG. 9 is a fragmentary, longitudinal sectional view of the form of block means and its mounting illustrated in FIG. 8, but drawn to an enlarged scale;

FIG. 10 is a view similar to FIG. 9 but showing a different form of block-mounting means;

FIG. 11 is a side elevation, drawn to a smaller scale, illustrating another form of spring member with block means secured thereto;

FIG. 12 is a plan view of a movable clipper blade having a different form of recess and showing the block means of FIG. 11 engaged in the blade recess, a fragment of the block-supporting spring being shown; and

FIG. 13 is a sectional view taken substantially on the line 13-13 of FIG. 12.

Referring more particularly to FIGS. 1 to 4 of the drawings, the reference numeral indicates generally a vibratory hair clipper including a case 21 and a vibratory electric motor indicated generally by the reference numeral 22 and comprising a coil 23 fixedly mounted in the case and a vibrating armature 24. A lower blade 25 is secured to the case 21 by suitable means such as the screws 26 and is formed to provide a transversely flat, upper surface 27 which, as is clearly shown in FIG. 1, is conventionally disposed in a plane which inclines upwardly and forwardly with respect to the plane of vibration of the armature 24. At its forward, transverse edge, the blade 25 is formed to provide a series of teeth 28.

Transversely slidably supported upon the upper surface 27 of the fixed blade 25 is an upper blade 29 formed at its forward, transverse edge with a series of teeth 30 for cooperation with the teeth 28 of the lower blade 25. The blade 29 is provided with a transversely flat lower surface 31 which mates with the flat upper surface 27 of the blade 25. A transversely-elongated recess 33 opens through the surface 32 of the blade 29 and, in the form of blade illustrated in FIGS. 1 to 4, said recess opens also through the lower surface of said blade.

An extension 34 secured to the armature 24 extends forwardly from,.said armature toward the blade 29 and, at its distal end, carries a spring element 35 which is resiliently flexible in directions substantially perpendicular to the plane of the surface 27 of blade 25, block means 36 receivable in the recess 33 being carried at the distal end of said spring element 35.

As illustrated in FIGS. 1 to 3, the blade 29 is a well known commercial product which is described in some detail in the patent to Wahl et al. 2,876,538, issued Mar. 10, 1959. As is most clearly illustrated in FIG. 3 of the present drawings, one lateral boundary of the recess 33 is defined, at least in part, by surfaces 37 and 38 which are inclined downwardly and toward each other and which converge as they progress laterally away from the opposite lateral boundary which, in turn, is defined, at least in part, by surfaces 39 and 40 which are inclined downwardly and toward each other and which converge as they progress laterally away from the surfaces 37 and 38. As will become apparent as the description proceeds, the block means at the distal end of the spring element according to the present invention is so proportioned and designed as to establish and maintain, with the surfaces 37, 38, 39

and 40, pointor line-contacts.

As is most clearly illustrated in FIG. 4, the spring element 35 is formed near its proximal end with an elongated slot 41 for the reception of suitable fastening means securing the spring element to the extension 34; and, near its distal end, it is formed with one or more perforations 42. In this form of the present invention, the block means 36 comprises a rectangular strip of formable material which is foldable upon itself to define mating lips 43 and 44 embracing the distal end region of the spring element 35 and defining a substantially part-cylindrical fold. The material of the block 36 may be a ductile metal such as brass or it may be a molded rubberoid material or a synthetic material. Where brass is used, the final folding operation may include heavy pressure which will so distort the brass as to cause it firmly to grip the spring end, it may include a step of pressing or striking the metal to form a dimple 45 whereby a portion of the block metal is distorted into one of the perforations 42, or other means may be used for firmly securing the formed block to the spring element. It will be seen that the resultant block means 36 is provided with square ends which are disposed in planes substantially perpendicular to the long axis of the block means and each of which comprises a part-circular edge so disposed that, when the block means is entered in the blade recess 33 with the spring element 35 flexed in a direction yieldably to urge the blade surface 31 into contact with the blade surface 27, the part-circular edge of the block end 46 will have line contact with the surfaces 37 and 38 while the part-circular edge of the block end 47 will have line contact with the surfaces 39 and 40.

It will be apparent that, with this arrangement, each surface 37, 38, 39 and 40 will be engaged, when the assembly is at rest, by only a short, curved, very narrow portion of the part-cylindrical edge of the block means 36. When the coil 23 is energized and the armature begins to move downwardly as viewed in FIG. 2, the edge regions of the end 47 of the block means 36 will exert force against the surfaces 39 and 40 to entrain the blade 29 in the armature movement. Since the distal end of the rigid extension 34 will tend to retreat from the plane of the surface 27 during this movement, with its leading edge retreating somewhat more rapidly than its trailing edge, the spring pressure urging the end 47 of the block means 36 toward the surface 27 will relax somewhat more rapidly than will the pressure urging the end 46 toward that surface, with the result that there will be a slight rolling movement of the block edges relative to the recess surfaces in a counter-clockwise direction as viewed in FIG. 1. It will be seen, however, that line contact is maintained during this rolling movement, at all four surfaces 37 38, 39 and 40. As the blade 29 is thus driven downwardly as viewed in FIG. 2, it acquires kinetic energy or momentum.

Now, as the armature 24 reaches the end of its downward stroke, it will stop. Since the mass of the block means 36 is so much smaller than the mass of the blade 29, the block means will stop almost simultaneously with the armature, but the blade will continue to move downwardly minutely before its kinetic energy is dissipated by the engagement of the surfaces 37 and 38 with the end 46 of the block means. As a consequence, the edge regions of said block end which are in contact with the surfaces 37 and 38 will be cammed minutely upwardly away from the surface 27; but because of the resiliency of the spring means 35, the regions of the block end 47 which are in line contact with the surfaces 39 and 40 will be caused to ride downwardly on those surfaces to a corresponding degree. Thus, the line contact between the block means 36 and all four surfaces 37, 38, 39 and 40 will be maintained during dissipation of the kinetic energy of the blade 29 and, when the blade is entrained with the reverse movement of the block means 36 under the influence of the reverse movement of the armature 24, the line contacts of the block means with all four surfaces 37, 38, 39 and 40 will be maintained as the blade achieves synchronism with the armature. Since the distal end of the extension 34 will approach the surface 27 during movement of the block means 36 from the lower limit of its stroke to the median point of its stroke, the regions of contact between the block ends and the recess surfaces will return to their rest relationships by the time the armature has reached the median point of its stroke. Of course, the above-described cycle will be repeated in reverse as the armature attains the upper limit of its stroke as viewed in FIG. 2.

Because the regions of contact between the recess surfaces and the cooperating edge portions of the block means 36 are minute in their cumulative areas, and because contact is maintained in all four of those regions by the above described rolling action, no noise-producing slap will occur during operation of the mechanism and the degree of wear upon the contacting surfaces during the life of the mechanism is radically reduced as compared with previously known drive trains.

In FIG. 5, I have illustrated a dilferent form of block means which achieves point contact rather than line contact between the block means and the recess abutment surfaces. A spring element, 49, in all respects equivalent to the spring element 35, is here provided with block means 50 which is similar to the block means 36 except that the lateral end regions 51 and 52 of the block means 50 are formed to substantially part-spherical shape during the folding and pressing operation above described. Thus, the block means 50 will have point contact, rather than line contact, with the surfaces 37, 38, 39 and 40 of the blade recess 33.

In the form shown in FIG. 6, a spring element 53 similar to the spring element 35 is provided with block means 54 which is similar to the block means 36 except that rounded heads 55 and 56 are provided at the opposite ends of the block means. In this case, the heads 55 and 56 may be mere buttons, welded or otherwise secured to the square ends of the folded element 54, or they may be headed pins with their shanks entered, and suitably secured, in the part-cylindrical end regions of the folded block element.

FIG. 7 shows a further modified assembly comprising a similar spring 57 equipped with separate block elements 58 and 59 suitably folded upon, and secured to, the lateral end regions of the distal portion of the spring. As shown, the elements 58 and 59 are formed to provide substantially part-spherical end regions 60 and 61 to provide point contact with the recess abutment surfaces, but it will be apparent that such end regions could, instead, be squared to simulate the condition of FIG. 4. As shown, each of the pieces 58 and 59 is secured in place on the spring element by striking, as at 62 or 63, to dimple the block piece and, simultaneously, dimple the material of the spring, but it will be apparent that such pieces might be otherwise secured in place.

FIGS. 8 and 9 illustrate a different form of block piece. According to this form of the invention, the distal region of a spring 64 is equipped with a plate-like block 65 having, at its distal end, a part-cylindrical enlargement 66 defining a step or shoulder 67. The spring is formed with one or more perforations 68 so located that, when the distal extremity of the spring 64 is seated on the step 67, the material of the plate may be coined to penetrate said perforations and to define heads 69 securing the block to the spring. While the lateral ends of the enlargement 66 are illustrated as flat surfaces perpendicular to the axis of the enlargement to produce an action like that produced by the head 36 of FIG. 4, it will be clear that said end regions might be rounded to provide point contact with the recess abutment surfaces.

Obviously, other means could be provided for securing a block element similar to that illustrated in FIGS. 8 and 9 to a similar spring. For instance, in FIG. there is illustrated a fragment of a spring 74 formed with one or more perforations 73 and having mounted thereon a block 70 similar to the block 65 but formed with one or more perforations 71 for the reception of self-leading metal screws 72 which will force their way, and thread themselves through, the perforations 73.

FIG. 11 illustrates a still further form of spring and block element. In this instance, the spring 75 is formed with an out-turned toe 76 to the lower surface of which is welded a block element 77 which may be a cylindrical rod having either square ends or rounded ends. In FIGS. 12 and 13, I have shown this form of spring and block assembly operatively associated with a modified form of blade 29, though it will be apparent that the assembly of FIG. 11 could as well be used with the form of blade illustrated in FIG. 3.

The blade 29' is formed with a recess or socket 78 opening therethrough but defined by downwardly inclining lateral end surfaces 79 and 80 and parallel transverse walls 81 and 82 which may be perpendicular to the bottom surface of the blade. In this case, the ends 83 and 84 of the block means 77 are part-spherical so that the block end 83 has point contact with the inclined surface 79 while block end 84 has point contact with the inclined surface 80. It will be clear, of course, that throughout the above-described action, such point contact will be consistently maintained. It will also be apparent that the form of block means illustrated in FIG. 6 or any other form illustrated herein, could be used with the form of blade illustrated in FIG. 12.

What is claimed is:

1. In a vibrator type electric hair clipper comprising a vibratory electric motor including a coil and an armature, a first toothed blade fixed relative to said coil and having an upper surface, a second toothed blade having a lower surface reciprocably disposed in face-to-face relation to said upper surface of said fixed blade, said reciprocable blade being formed to provide laterally-spaced abutment means each defined, at least in part, by a surface which is inclined downwardly and toward the other abutment means; the invention which comprises a spring element fixed to said armature and extending toward said reciprocable blade, said spring element being resiliently flexible in directions substantially perpendicular to said upper surface of said fixed blade, and said spring element further being provided with block means at its distal end receivable between said abutment means, the lateral ends of said block means being shaped for non-conforming, concurrent contact with said inclined surfaces with said spring element flexed to urge said second blade yieldably into contact with said fixed blade and to drive said reciprocable blade, said block means being formed from sheet metal folded upon itself to define substantially semicircular edges at the lateral boundaries of its distal end.

2. In a vibrator type electric hair clipper comprising a vibratory electric motor including a coil and an armature, a first toothed blade fixed relative to said coil and having an upper surface, a second toothed blade having a lower surface reciprocably disposed in face-to-face relation to said upper surface of said fixed blade, said reciprocable blade being formed to provide laterally-spaced abutment means each defined, at least in part, by surfaces which converge as they progress laterally away from the other abutment means and which are inclined downwardly and toward the other abutment means; the invention which comprises a spring element fixed to said armature and extending toward said reciprocable blade, said spring element being resiliently flexible in directions substantially perpendicular to said upper surface of said fixed blade, and said spring element further being provided with block means at its distal end receivable between said abutment means, the lateral ends of said block means being shaped for non-conforming, concurrent contact with said inclined surfaces with said spring element flexed to urge said second blade yieldably into contact with said fixed blade and to drive said reciprocable blade, said block means being formed from sheet metal folded 7 upon itself to define substantially semicircular edges, upon a radius less than one-half the miximum distance between said converging surfaces of each abutment means, at the lateral boundaries of its distal end.

References Cited UNITED STATES PATENTS 1,582,320 4/1926 Wahl 30-221 8 A n Lutes 30-210 Volz 30-210 Rolstad 30-210 Wahl 30-210 Andis 30-210 Andis 30 -210 GRANVILLE V. COSTER, 111., Primary Examiner 

